Vacuum type blank feeding device with positive on/off control



T. R. BAKER ETAL 7 May 14, 1963 VACUUM TYPE BLANK FEEDING DEVICE WITH POSITIVE ON/OFF CONTROL 6 Sheets-Sheet 1 Filed Oct. 9, 1961 INVENTORS 7/10/7708 A. Baker BY Bar/ls 6. Poser! {W ATTORNEY May 14, 1963 T. R. BAKER ETAL 3,089,698

VACUUM TYPE BLANK FEEDING DEVICE WITH POSITIVE ON/OFF CONTROL Filed Oct. 9, 1961 6 Sheets-Sheet 2 3 O 2a 34 3 5 9 A \W I I Fig. 2 INVENTORS homas R. Baker BY Sons 6. Poser] l A TTORWEY May 14, 1963 T. R. BAKER ETAL 3,089,698

VACUUM TYPE BLANK FEEDING DEVICE WITH POSITIVE ON/OFF CONTROL Filed Oct. 9, 1961 6 Sheets-Sheet 5 4 o E x CD==T=I 28 Q 53 5; /9 f 52 Q 54 48 O 34- P l I 9 1/ 9 A 29 36 O INVENTORS Flag 3 Thomas R. Baker Boris 6. Pose/7 BY W W l W ATTORNEY May 14, 1963 T. R. BAKER ETAL 3,089,693

VACUUM TYPE BLANK FEEDING DEVICE WITH POSITIVE ON/OFF CONTROL Filed Oct. 9, 1961 e Sheets-Sheet 4 ill QB] INVENTORS Thomas R Baker Ear/' 5: Pose A TTORWEY May 14, 1963 T. R. BAKER ETAL 3,089,698

VACUUM TYPE BLANK FEEDING DEVICE WITH POSITIVE ON/OFF CONTROL.

Filed Oct. 9, 1961 6 Sheets-Sheet 5 INVENTORS Thomas R. Baker Bar/s 5. Pose/7 A TTORNEY y 14, 1963 T. R. BAKER ETAL 3,089,698

VACUUM TYPE BLANK FEEDING DEVICE WITH POSITIVE ON/OFF CONTROL 6 Sheets-Sheet 6 Filed Oct. 9, 1961 IN V EN TORS Thomas R. Baker Boris 5. Poser;

l M ATTORNEY United States Patent Ofi ice 3,089,698 Patented May 14, 1963 3,039,698 VACUUM TYPE BLANK FEEDING DEVICE WITH POSITIVE ON/OFF CONTROL Thomas R. Baker and Boris S. Posen, Los Aitos, Calif.,

assignors to Atlas General Industries, 1nd, New York,

N.Y., a corporation of Massachusetts Filed Oct. 1961, Ser. No. 143,778 Claims. (Cl. 27156) This invention relates to devices for feeding individual box blanks by suction cups from a pick-up station, for example the magazine of a folding box machine, to a delivery station, for example the folding die of the machine through which the blank is subsequently forced by a plunger to fold the blank into box form.

The invention deals with improvements of such blank feeding devices to render the operation of the devices positive, in the sense ofeliminating existing causes of misfeeding and misdelivery of blanks.

Automatic box formens generally form a part of a packaging line in which a product is automatically or manually inserted into the box former only a very brief period previously. Where the supply of the product is irregular the production of boxes must be interrupted from time to time to prevent an excessive number of boxes from accumulating in the box delivery line.

This is generally accomplished by installing a suitable sensing device in the box delivery line todetect an accumulation of boxes therein. A photoelectric cell, for example, may be employed which produces appropriate demand or no-demand signals, and the signals may be impressed on a suitable servo-rnechanism which interrupts the flow of blanks to the machine. In blank feeders of the vacuum type this is readily accomplished by interrupting the vacuum to, or venting the vacuum at, the suction cup or cups which grip the blanks.

A difficulty with this known and commonly used arrangement is an occasional mistiming of the moment the vacuum is either interrupted or restored, leading to misfeeding of a blank and consequent jamming or other interference with the box former.

Assuming, for example, that the box former is equipped with a magazine from which blanks may be withdrawn, one by one, by the feeder, and assuming that the box former is of the plunger and die type, it may first be assumed that the vacuum is interrupted after the suction cup device picked up a blank, but prior to delivery in the precise location where the plunger subsequently engages the blank and drives it through the die. Interruption of the vacuum causes the blank to be dropped prematurely and the operation of the machine is disturbed by jamming, formation of a misshaped box, or otherwise.

Next, it may be assumed that the vacuum was interrupted for a period and is restored shortly after the suction cup has begun to withdraw from the magazine but at a point where the suction is still sufficiently powerful to withdraw, or at least partially withdraw, the blank from the magazine. If withdrawn entirely, the blank is nevertheless likely not to be grasped in the proper manner and position on which the accuracy of the subsequent deposit depends, but is likely to have shifted, leading to formation of a misshapen box or even jamming.

If, on the other hand, the blank is only partially withdrawn from the magazine and then separated from the suction cup or cups, it will be improperly grasped during the next feeder stroke with equally disturbing results.

The invention eliminates these difiiculties by an improvement which prevents the control mechanism from restoring or relieving vacuum at periods of the feeder cycle at which a blank would be dropped, dislocated or improperly placed.

More particularly, the feeder is prevented from changing from vacuum to relief, or from relief to vacuum, when the suction cup or cups are near the magazine, or pick-up station. Also, the feeder is prevented from dropping a blank carried by it after performing only a portion of the delivery stroke.

Expressing the improved feeder operation in human terms, the feeder is forced to make up its mind to feed or not to feed prior to approaching the magazine so closely that vacuum might disturb the blanks in the magazine. Having made up its mind to feed, the feeder is forced to carry out its full delivery stroke, even though a nodemand signal may be received after the feeder has traveled only through a portion of its delivery stroke. The no-demand signal, however, becomes effective after completion of the delivery stroke, so that no blank is picked up during the next cycle.

If, on the other hand, the feeder has been idling during a no-demand period, a demand signal remains ineffective for a further cycle, if received too late to ensure secure gripping of the next blank.

These and other objects, features and advantages of this invention will appear more fully from the detailed description which follows accompanied by drawings showing, for the purpose of illustration, a preferred em bodiment of the invention. The invention also resides in certain original features of construction and combination of elements hereinafter set forth and claimed.

Although the characteristic features of this invention which are believed to be novel will be particularly pointed out in the claims appended hereto, the invention itself, its objects and advantages, and the manner in which it may be carried out, may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part of it in which:

FIGS. 1 to 4 are perspective views of a portion of a box forming machine comprising a blank feeding mechanism incorporating the invention, successive phases of operation being shown in FIGS. 1 and 2, nodemand and demand conditions being shown in FIGS. 3 and 4, re spectively;

FIG. 5 is a sectional view of a demand-controlled valve of the mechanism shown in FIGS. 1 to 4;

FIG. 6' is a diagrammatic illustration of the feeder operation within a demand period; and

FIG. 7 is a diagrammatic illustration of the feeder operation within a no-blank-demand period.

In the description and in the claims various details will be identified by specific names for convenience. The names, however, are intended to be generic in their application. Corresponding reference numerals refer to corresponding parts in the several figures of the drawings.

The drawings accompanying, and forming part of, this specification disclose certain specific details of construction for the purpose of explanation of broader aspects of the invention, but it is understood that structural details may be modified in various respects without departure from the principles of the invention and that the invention may be incorporated in other structural forms than shown.

The box forming machine, of which a portion is shown in FIGS. 1 to 4, is essentially a plunger and die type machine for producing g-lued boxes. Such machines are disclosed in detail for example in the patent to Pagendarm No. 3,038,389, dated June 12, 1962.

The machine is equipped with a pneumatic blank feeding mechanism for removing substantially vertically dis posed flat blanks from a blank magazine and placing them in substantially horizontal position over the mouth of a box forming die through which a plunger then forces the blank to fold it into box form about the plunger.

Blank feeding mechanisms of a geometry appropriate for this purpose are known and are fully disclosed, for

3 example, in the prior patents to Baker and Pagendarm No. 2,624,249 of January 6, 1953, and to F. M. Lefief No. 2,805,060 of September 3, 1957. It is therefore not necessary to describe and illustrate the operating mechanism of the feeding mechanism in detail in this specification.

Suflice it to say that the feeder mechanism is timed with respect to the plunger movement so as to deposit a blank at the mouth of the forming die while the plunger is retracted, and to move out of the way of the plunger in time to permit the plunger to enter the die and shape the box. In the meantime, the feeder moves to the magazine to pick up a new blank in case of demand, or to perform an idle stroke while there is no demand for blanks.

Turning to FIG. 1, a portion of the blank magazine is visible at the right comprising a magazine gate frame 11 from which a pair of blank supporting rods extend to the rear, one such rod being visible at 12. A stack of blanks B rests on the rods 12 on edge and are laterally kept in line by further rods 13. Lips are provided for preventing the frontmost blank from falling out of the magazine, one such lip being on the end 14 of bracket 15. The retaining lips overlap the frontmost blank slightly, the overlap being of the order of of an inch, and slight flexing of the blank resulting from withdrawal of the blank by a suction cup or cups is suflicient to permit the blank to clear the retaining lips.

The blank magazine represents the blank removal station. The blank deposit station is partially visible in the background. It is flanked by four glue applicators of which two are seen at 16. The applicators are mounted approximately at the four corners of a die aperture which is not visible, but is indicated in FIGS. 6 and 7. Liquid adhesive is supplied to the applicators through flexible ducts 17. Appropriate elements are provided for aligning the blank with respect to the die, one such element being shown as having the form of an L bracket 18.

Referring to FIGS. 1 and 4, a feeder bar 19 of square cross section extends between arms 20 supported on the machine frame at 21. The feeder bar 19 carries a feeder head 22 comprising suction cups 23 projectible and retractable by means of a bellows 24, and further comprising a folding frame 25 which bears down upon the blank carried by the suction cups adjacent certain fold lines to assist in folding the blank when the blank B is being deposited between the adhesive applicators 16.

FIG. 6 illustrates the path of the feeder between the blank removal station and the blank deposit station. Three distinct positions of the feeder head are shown and, in addition, six further positions of the feeder bar 19 are indicated to designate the path being traversed by the feeder. Suitable operating mechanism for producing this and similar motions are known and are disclosed, for example, in the aforementioned three patents.

It is seen that the feeder head 22 first backs away from the blank stack in the magazine and takes a blank with it. The feeder bar 19 then performs a compound rotative and translatory motion during the major portion of which the blank moves edge first, so as to encounter a minimum of air resistance.

After approximately 90 degrees of feeder bar tilt the blank is put down between the adhesive applicators 16 and above the folding die 26. There the blank is released by relieving the vacuum applied to the suction cups.

Referring to FIG. 4, a vacuum duct is shown at 27 and 28. Portion 27 of the duct extends between a conventional vacuum pump (not shown) and a control valve 29. Portion 27 is under vacuum at all times. Portion 28 extends between the control valve 29 and the suction cups.

The control valve comprises a stationary valve body 30 and a rotatable valve member 31 fitted with a vane 32 for oscillating the valve body about its axis. The duct portion 28 leads to the valve body and terminates in a bore in a cylindrically curved valve face in which the cylindrical valve member 31 is craded with an airtight fit. The valve member 31 also has a bore 33 through it from which the duct portion 28 extends.

In one extreme position shown in FIGS. 1, 3 and 4 the bore 33 in the valve member 31 is in line with the bore in the valve body, i.e., the end of duct 28. In this position vacuum is applied to the suction cups.

In the other extreme position shown in FIG. 2, the valve member 31 is rotated so as to bring its bore 33 in communication with the atmosphere. In this position the vacuum in line 28 is vented and atmospheric pressure prevails therein. Line 27 is shut off at the valve body where the cylindrical surface of the valve member 31 closes the bore in the valve body 30.

Tilting of the valve member 31 is effected by two abutments 34 and 35 in the form of ball bearings on a lever 36 which is oscillated in time with the driving mechanism. When the feeder head aproaches the magazine at the end of the return stroke the main valve 29 is in the position in which ducts 27 and 28 are connected so as to apply vacuum to the suction cups (FIG. 4). When the feeder head reaches the deposit station at the end of the feed stroke (FIG. 2) the valve 29 vents line 28 to the atmosphere, so that the blank is released.

Turning now to the improvement provided by the invention, a second or demand valve is installed in the vacuum line to prevent the feeding of blanks during periods of no demand, for example during a period of scarcity of articles to be packaged and an oversupply of boxes.

While the demand valve may be installed in a number of locations, it is particularly advantageous to mount it in a position close to the suction cups together with the movable portion of the feeder so as to travel with the feeder head. This form' of installation makes the mechanism particularly simple.

The demand valve 37 in the illustrated embodiment is mounted on the feeder bar 19 which, for convenience of construction, is provided with an offset portion 38.

Details of the demand valve are shown in FIG. 5.

The demand valve comprises a body 39 having a bore 40 into and from which vacuum line 28 extends at ports 41 and 42. A vent port 43 is normally closed by a resilient valve member 44 on an arm 45 pivoted at 46 and biased by a safety pin type spring 47 tending to maintain the vent port 43 sealed.

The arm is provided with a slanted or inclined cam surface, the purpose of which will immediately become apparent.

As seen in FIGS. 3 and 4, the portion of duct 28 which extends from the main control valve 29 enters the demand valve body at the remote port 42, and the portion of the duct 28 continuing to the suction cups extends from the near port 41.

It is evident that opening of the vent port 43 of the demand valve prevents vacuum from being applied to the suction cups, as the vacuum pump will draw air through lines 27, first portion of line 28, bore 40 and port 43.

An actuator is provided for opening the demand valve during periods of no blank demand, and the actuator is so constructed and arranged as to actuate the valve only during a certain portion of the feeder stroke and, further, in such a Way as to make it impossible for the valve position to change during that portion even though the signal may change from demand to no demand or vice versa.

The demand sensor may have the conventional form of a photoelectric cell and a source of light emitting a beam of light directed at the cell and interrupted when boxes accumulate in the box discharge line. Generally, two such photoelectric units are provided, combined with a single relay which produces an appropriate signal when both light beams are broken as in the case of a box jam, but which produces no signal if only one beam is broken by a passing box. Such devices are known and need not be described in greater detail. The relay then operates a suitable servo-device. In the illustrated blank feeding mechanism the servo-device has the form of an electromagnet comprising a field winding 49 and a movable armature 50 biased by a spring 51 normally to assume a released position as shown in FIGS. 1, 2 and 4.

The lower end of the armature 50 engages one arm of a double armed lever 52 carrying a roller 53 at the other arm. The lever is pivoted at 54 with the result that the roller 53 is raised and moved into the path of the cam surface 48 of the demand valve 37 when the electromagnet is energized and pulls up its armature 50 (see FIG. 3).

The lever 52 may be considered a semaphore arm which the demand valve 37 only sees, or rather feels, when the feeder bar 19 has reached the terminal portion of its return stroke. If the semaphore arm 52 is down, as in FIGS. 1, 2 and 4, the demand valve takes no notice and remains closed even though the signal may change during the terminal portion of the return stroke or the initial portion of the feed stroke of the feeder.

It is seen from FIG. 4 that raising of the roller 53 at the illustrated moment is ineffective to depress the arm 45 of the demand valve. The roller 53 will engage the underside of the arm 45, but not the cam surface 48, hence not open the valve. As a result, the vacuum is not interrupted and a blank is fed.

If the no demand signal continues and the roller remains raised, the demand valve will continue to vent the feeder vacuum during the next feed cycle, as the arm 45 of the demand valve will be deflected by the roller 53 when the feeder next approaches the magazine 11, as shown in FIG. 3.

Conversely, it is seen that at the moment illustrated in FIG. 3 a change of the signal to demand and a consequent deenergizing of the electromagnet remains ineffective as the demand valve 37 remains open until the feeder has moved some distance away from the magazine. The distance is great enough that restoration of the vacuum at the suction cups will not displace any blank in the magazine. The distance may be regulated by shifting the valve 37 towards or away from the observer, installation of a valve arm 45 of different length, change of the cam shape 48, and in other ways.

Should, therefore, the signal change from no demand to demand at the moment illustrated in FIG. 3, the feeder will nevertheless perform one idle feed stroke, but resume feeding blanks thereafter, as long as the demand signal continues.

While the feeder is carrying a blank from the magazine to the deposit station a change in the signal to no demand has no effect on the blank being carried, as the demand valve is beyond reach of the actuator lever 52. There is therefore no danger of the blank being carried only part way and then dropped, which would disturb the proper functioning of the box former.

It is evident that the invention may be incorporated in, or performed by, other specific forms of apparatus. The invention offers advantages similar to those described in the feeding, by vacuum, of blanks or sheets to be printed, partially or completely folded trays and boxes to be fed, and labels to be attached.

Appropriate modifications and adaptations Of the mechanism for specific purposes suggest themselves to persons skilled in the art on the basis of the teaching of the invention.

What is claimed is:

1. A blank feeding device comprising, in combination, a carrier movable through its stroke between a blank pickup station and a blank deposit station; a suction cup on said carrier; a source of vacuum including a line extending to said cup; a control valve in said line for applying and relieving vacuum at the respective ends of the stroke; a blank demand responsive means; a demand valve in said line operated by said demand responsive means for applying and relieving vacuum in response to demand conditions; and means operative within a portion of the stroke adjacent the pick-up station for preventing a change in the position of the demand valve within said stroke portion.

"2. A blank feeding device comprising, in combination, a carrier movable through its stroke between a blank pick-up station and a blank edposit station; a suction cup on said carrier; a source of vacuum including a line extending to said cup; a control valve in said line including means for operating said control valve to apply and relieve vacuum at the respective ends of the stroke; means for producing two distinct signals, viz. blank demand, and no demand; a demand valve in said line responsive to said signals for maintaining and relieving vacuum independent of said control valve; and means operative within the terminal portion of the stroke adjacent the pick-up station for rendering the demand valve non-responsive to a change in the signal within said portion.

3. A blank feeding device, comprising, in combination, a carrier movable through its stroke between a blank pickup station and a blank deposit station; a suction cup on said carrier; a source of vacuum including a line extending to said cup; a control valve in said line for applying and relieving vacuum at the respective ends of the stroke; a blank demand responsive means; a demand valve in said line and mounted on said carrier; and an actuator for said demand valve, said actuator being operated by said demand responsive means, said actuator being fixedly mounted relatively to said pick-up station and so located relatively to said carrier path as to set and maintain the demand valve in one or the other position within the terminal portion of the carrier stroke at the pick-up station.

4. A blank feeding device comprising, in combination, a carrier movable through its stroke between a blank pick-up station and a blank deposit station; a suction cup onsaid carrier; a source of vacuum including a line extending to said cup; a first valve in said line for applying vacuum to, and venting vacuum at said cup, respectively; means responsive to the position of the carrier relatively to its path for operating said first valve; a second valve in said line for venting vacuum at said cup independently of said first valve; means responsive to the demand for blanks for operating said second valve; and means for locking said second valve against change of its setting, said locking means being effective'during a portion of the stroke of the carrier adjacent the pick-up station.

5. A blank feeding device comprising, in combination, a source of vacuum; a suction cup; power means for moving said suction cup between a blank pick-up station and a blank deposit station; first valve means including a duct to said source for alternately applying vacuum from said source to said cup and relieving vacuum at said cup, said valve means being operated in response to the position of said cup relatively to said two stations; second valve means in said duct for relieving vacuum at said cup independently of said first valve means, said second valve means having one setting in which vacuum is vented and another position in which vacuum is not vented; means responsive to demand for blanks for actuating said second valve means during its movement towards the pick-up station; and means for rendering said actuating means ineffective to change the valve setting during a terminal portion of the suction cup movement towards said pick-up station.

6. A blank feeding device comprising, in combination, a suction cup carrier; a suction cup on said carrier; a blank magazine representing a blank withdrawal station; means forming a blank deposit station; power means for reciprocating said carrier between said two stations to perform a feed stroke and a return stroke, respectively; a source of vacuum; a vacuum line extending from said source to said cup; a first valve in said line, said valve being operated in timed relationship with said power means for alternately applying vacuum to said cup and relieving vacuum at said cup; a second valve in said line adapted, upon actuation, to relieve the vacuum at said cup independent of said first valve, said second valve being mounted on said carrier; means responsive to demand and non-demand for blanks respectively, said demand response means comprising a movable element positioned to actuate and maintain said second valve actuated in the no-demand position during the terminal portion of the return stroke and during the initial portion of the feed stroke, said movable element clearing said valve without actuating it, when in the demand position.

7. A blank feeding device comprising, in combination, a suction cup carrier; a suction cup on said carrier; a blank magazine representing a blank withdrawal station; means forming a blank deposit station; power means for reciprocating said carrier between said two stations to perform a feed stroke and a return stroke, respectively; a source of vacuum; a vacuum line extending from said source to said cup; a first valve in said line; said valve being operated in timed relationship with said power means for alternately applying vacuum to said cup and relieving vacuum at said cup; a second valve in said line adapted, upon actuation, to establish communication between said line and the atmosphere to relieve vacuum at said cup, said second valve being mounted on said carrier and comprising a movable valve actuating member; a movable element mounted at said magazine with freedom to assume a first position in which it engages and deflects said member, and a second position in which it clears said member during the terminal position of the return stroke and the initial portion of the feed stroke; blank demand responsive means for moving said element into engaging position during a condition of no demand and into clearing position during a condition of blank demand, said actuating member and said element being so dimensioned as to bring the actuating member within reach of said element just prior to contact of said cap with blanks in the magazine during the return stroke and to maintain the member within reach of said element until after the cup has cleared the blanks during the feed stroke.

8. A blank feeding device comprising, in combination, a suction cup carrier; a suction cup on said carrier; a blank magazine representing a blank withdrawal station; means forming a blank deposit station; power means for reciprocating said carrier between said two stations to perform a feed stroke and a return stroke, respectively; a source of vacuum; a vacuum line extending from said source to said cup; a first valve in said line, said valve being operated in timed relationship with said power means for alternately applying vacuum to said cup and relieving vacuum at said cup; a second valve in said line at said cup; a vent valve mounted on said carrier for venting said line to the atmosphere, said vent valve comprising an arm directed towards said magazine; a movable element mounted at said magazine for engaging and deflecting said valve arm in one position of said element to vent the line, and for clearing the valve arm in another position in which other position the vent valve remains :closed; and blank demand responsive means for moving said element into one or the other position in response to .no demand, and blank demand, respectively.

9. A device as set forth in the preceding claim 8 in which said movable element is a roller and in which said arm is provided with an inclined cam surface for engaging said roller in said one position.

10. A blank feeding device comprising, in combination, a suction cup carrier; a suction cup on said carrier; a blank magazine representing a blank withdrawal station; means forming a blank deposit station; power means for reciprocating said carrier between said two stations to perform a feed stroke and a return stroke, respectively; a source of vacuum; a vacuum line extending from said source to said cup; a first valve in said line, said valve being operated in timed relationship with said power means for alternately applying vacuum to said cup and relieving vacuum at said cup; a second valve in said line at said cup; a vent valve mounted on said carrier for venting said line to the atmosphere, said vent valve comprising an arm directed toward said magazine; a lever mounted at said magazine in a location in which it lifts the valve arm in one position to vent the line and clears the arm in the other position in which the vent valve remains closed; and blank demand responsive means for moving said lever into one or the other position in response to no demand, and blank demand, respectively, the lever and arm being so dimensioned as to reach a position of engagement prior to contact of said cup with blanks in the magazine.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A BLANK-FEEDING DEVICE COMPRISING, IN COMBINATION, A CARRIER MOVABLE THROUGH ITS STROKE BETWEEN A BLANK PICKUP STATION AND A BLANK DEPOSIT STATION; A SUCTION CUP ON SAID CARRIER; A SOURCE OF VACUUM INCLUDING A LINE EXTENDING TO SAID CUP; A CONTROL VALVE IN SAID LINE FOR APPLYING AND RELIEVING VACUUM AT THE RESPECTIVE ENDS OT THE STROKE; A BLANK DEMAND RESPONSIVE MEANS; A DEMAND VALVE IN SAID LINE OPERATED BY SAID DEMAND RESPONSIVE MEANS FOR APPLYING AND RELIEVING VACUUM IN RESPONSE TO DEMAND CONDITIONS; AND MEANS OPERATIVE WITHIN A PORTION OF THE STROKE ADJACENT THE PICK-UP STATION FOR PREVENTING A CHANGE IN THE POSITION OF THE DEMAND VALVE WITHIN SAID STROKE PORTION. 